1. Technical Field
The present invention relates to a quantitative detection device for measuring the concentration of a sample solution and more particularly to a quantitative micro-volume nucleic acid detection device having a first shielding screen, a second shielding screen, a lower glass plate, and an upper glass plate.
2. Description of Related Art
Conventionally, the concentration of a sample solution is measured by the Beer-Lambert law, also known as Beer's law, by injecting the solution into a quartz tube, projecting a light beam through the solution, measuring the transmittance of the solution over the entire spectrum with a conventional spectrophotometer, calculating the absorbance of the solution by reference to the intensity of the light, and estimating the concentration of the solution according to the relation between absorbance and concentration.
Since the major spectral range involved in the aforesaid computation is the ultraviolet band between 200 nm (nanometer) and 400 nm, the conventional methods and devices for measuring the concentration of a sample solution requires the sample solution to be placed in a quartz tube, for a tube made of other materials, such as glass, may absorb the light emitted by a light source of that particular waveband. Consequently, the conventional measuring techniques are disadvantaged by the high cost of quartz tubes. Other disadvantages include the required use of a relatively large amount of sample solution, poor repeatability (or reproducibility) of measurement, and difficulty in quartz tube cleaning.
Around 2004, a modified technique for measuring the concentration of a sample solution was proposed, in which measurement over a specific waveband is conducted by bringing an upper and a lower fiber-optic connector arm into contact with a sample solution and then pulling the arms apart through a solenoid valve to produce the desired variable optical path length.
As this prior art controls the variation of the optical path by opening and closing the solenoid valve, the mechanism is prone to collision while the two planes on which the fiber-optic connectors are respectively located draw near, and the collision may cause loosening or shifting of screws such that the optical path deviates from what is expected and therefore needs calibration. Also, this prior art tends to leave behind residues of the sample solution, which results in unrepeatable/unreproducible of the measurement problem. Furthermore, the problem which issued from attenuation of light intensity that caused by the prolonged usage of fiber-optic components may lower the accuracy of measurement.
Hence, it has been a major goal of innovation in the metrology instrument industry as well as the bio-medical instrument to develop a quantitative micro-volume nucleic acid detection device which is accurate and easy to use, which has a fixed optical path length during measurement, which does not require liquid compression respectively, which shows inventiveness by eliminating the need for calibration, which uses readily cleanable planar quartz glass plates that will not impair the repeatability/reproducibility or accuracy of measurement, and which solves the problems of the conventional micro-volume spectrophotometers while reducing the cost of measurement.